Currently there is no in-process method for tracking Fiber Bundle Volume (FBV) of filters used in hemodialysis and hemofiltration. Clotting reduces the effective filter volume and therefore impacts treatment delivery (Kt/V) for ESRD and acute renal failure patients. On-line FBV measurements would allow clinicians to maintain filter volume through timely saline flushes, and reduce anticoagulant dosage to a necessary minimum. Transonic Systems Inc. recently introduced a novel ultrasound indicator dilution method for on-line monitoring of FBV; the method could become a quality standard for hemodialysis and hemofiltration. The subject grant will fund the development and clinical validation of an accurate, easy to use FBV meter that will work with all existing hemodialysis and hemofiltration apparatus. During Phase I we will perform bench validations to establish absolute accuracy and reproducibility of this novel technology. Our four clinical collaborators will demonstrate feasibility in ESRD and acute renal failure settings, and investigate how this technology can improve treatment adequacy and optimize anticoagulant administration. During Phase II we will design both a low-cost portable version and an "OEM' embedded version of the FBV apparatus, and pursue multicenter patient studies and FDA clearance for areas where this technology could become the standard of care. PROPOSED COMMERCIAL APPLICATION: An on-line Fiber Bundle Volume monitor could become a routine measurement tool for dialysis and hemofiltration, first as a portable device, then as an internal component of treatment machines. This technology will improve dialysis delivery, reduce management costs, and improve the quality of life for ESRD and acute renal failure patients. This device is marketable in every hemodialysis center and ICU.